The present invention relates to a cylindrical lock and, more particularly, to a durable cylindrical lock.
Cylindrical locks on the market generally include inner and outer operational devices that can be operated to retract a latch through a retractor. The inner operational device includes an inner chassis, an inner spindle, and an inner handle. The outer operational device includes an outer chassis, an outer spindle, and an outer handle. Each of the inner and outer handles includes a lug for moving the retractor. To allow pivotal connection with the inner and outer spindles while preventing disengagement of the inner and outer spindles, each of the inner and outer spindles includes a space and an axial hole for pivotally receiving the inner or outer spindle. Furthermore, a torsion spring is mounted in each of the inner and outer chassis for returning the inner or outer spindle. To restrain the pivotal movement of the inner and outer spindles, the space of each of the inner and outer chassis includes an arcuate movement groove having two stepped portions spaced by an angle not larger than 180°, reducing the risk of deformation of the lug. However, the inner and outer chassis are generally made of the same material as the inner and outer spindles. The inner peripheries of the spaces and the axial holes of the inner and outer chassis are liable to wear due to pivotal movement of the inner and outer spindles. Furthermore, two tangs of each torsion spring must be twisted before the torsion springs are mounted in the inner and outer chassis, leading to difficulties in assembly.
Thus, a need exists for a novel cylindrical lock that can avoid wear to the inner and outer chassis while allowing easy assembly.